Question: When did Maine have a population of 847,226 people?
Paraphrase: What year was Maine's population estimated at 847,226 people?
SPARQL (Wikidata): SELECT ?value WHERE { wd:Q724 p:P1082 ?s . ?s ps:P1082 ?x filter(contains(?x , '847226.0')) . ?s pq:P585 ?value}